the output switch was turned back on and I had recovered my wits, so to
speak, I continued to play with the master switch, flipping it back and forth. I
found that with the exception of the transitional click, I could detect no trace of
a difference. I could switch in mid-utterance, and the sentence I had begun
speaking under the control of Yorick was finished without a pause or hitch of
any kind under the control of Hubert. I had a spare brain, a prosthetic device
which might some day stand me in very good stead, were some mishap to be-
fall Yorick. Or alternatively, I could keep Yorick as a spare and use Hubert.
It didn’t seem to make any difference which I chose, for the wear and tear
and fatigue on my body did not have any debilitating effect on either brain,
whether or not it was actually causing the motions of my body, or merely
spilling its output into thin air.
The one truly unsettling aspect of this new development was the prospect,
which was not long in dawning on me, of someone detaching the spare—
Hubert or Yorick, as the case might be—from Fortinbras and hitching it to yet
another body—some Johnny-come-lately Rosencrantz or Guildenstern. Then (if
not before) there would betwopeople, that much was clear. One would be me,
and the other would be a sort of super-twin brother. If there were two bodies,
one under the control of Hubert and the other being controlled by Yorick, then
which would the world recognize as the true Dennett? And whatever the rest
of the world decided, which one would beme? Would I be the Yorick-brained
one, in virtue of Yorick’s causal priority and former intimate relationship with
the original Dennett body, Hamlet? That seemed a bit legalistic, a bit too redo-
lent of the arbitrariness of consanguinity and legal possession, to be convincing
at the metaphysical level. For, suppose that before the arrival of the second
body on the scene, I had been keeping Yorick as the spare for years, and letting
Hubert’s output drive my body—that is, Fortinbras—all that time. The Hubert-
Fortinbras couple would seem then by squatter’s rights (to combat one legal
intuition with another) to be the true Dennett and the lawful inheritor of
everything that was Dennett’s. This was an interesting question, certainly, but
not nearly so pressing as another question that bothered me. My strongest intu-
ition was that in such an eventualityIwould survive so long aseitherbrain-
body couple remained intact, but I had mixed emotions about whether I should
want both to survive.
I discussed my worries with the technicians and the project director. The
prospect of two Dennetts was abhorrent to me, I explained, largely for social
reasons. I didn’t want to be my own rival for the affections of my wife, nor did I
like the prospect of the two Dennetts sharing my modest professor’s salary.
Still more vertiginous and distasteful, though, was the idea of knowingthat
muchabout another person, while he had the very same goods on me. How
could we ever face each other? My colleagues in the lab argued that I was
ignoring the bright side of the matter. Weren’t there many things I wanted to
do but, being only one person, had been unable to do? Now one Dennett could
stay at home and be the professor and family man, while the other could strike
out on a life of travel and adventure—missing the family of course, but happy
in the knowledge that the other Dennett was keeping the home fires burning.
I could be faithful and adulterous at the same time. I could even cuckold
myself—to say nothing of other more lurid possibilities my colleagues were all
Where Am I? 31